Tories



W 1 TNESS m iw w J. A. DOBLE.

LIQUID FUEL BURNER. APPLICATION FILED JULY 29. 1918.

Patented Dec 13, M213 '6,- llllli llillllllllllll/llllllllllllllilili/llflfl 4 INVENTOR [A 5051.4.

; A TTORNE YS UNITED STATES- PATENT OFFICE.

JOHN A. DOBLE, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO DOBLE LABORA- TORIES, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

LIQUID-FUEL BURNER.

Specification of Letters Patent.

Patented Dec. 13, 1921.

To all whom it may concern Be it known that I, JOHN A. DOBLE, a citizen of the United States, and a resident of the city and county of San Francisco and Stateof California, have invented certain new and useful Improvements in Liquid- Fuel Burners, of which the following is a specification.

The invention relates to liquid fuel burners in which the fuel is ignited by an electric spark and relates particularly to the ignition system.

An object of the invention is to provide an ignition system which eliminates the interrupter as an independent element.

A further object of the invention is to provide means for deriving an interrupted current from the direct current moto associated with the burner.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings I have shown one form of my invention, but it is to be understood that I do not limit myself to such form, since the invention, as expressed in the claims, may be embodied in a plurality of forms.

Referring to said drawings:

Figure 1 is a diagrammatic representation of one form of liquid fuel burner, showing the ignition system of my invention associated therewith.

Fig. 2 is a side view of the commutator of the motor associated with the burner.

Fig. 3 is an end View of the commutator.

The ignition system of my invention is applicable to all types of liquid fuel burners which are provided with electric motors either for directly or indirectly spraying or atomizing the fuel or introducing the necessary air for combustion or atomization. In the accompanying drawing I have shown a rotary type of burner in which a motor is employed for spraying the fuel and for introducing the necessary air for combustion.

Burners of the type to which the present invention-is applicable are used to a great extent on vehicles and in other locations, where the motor is driven by direct current from a storage battery or other source of supply.

The ignition spark requires an alternating or interrupted current of high voltage and this has been obtained from the source of direct current supply by a vibration and spark coil or by a motor driven interrupter and spark coil. It is the purpose of this invention to provide an ignition system which eliminates the use of an interrupter as a separate element or a vibrator, thereby increasing the simplicity of the system.

The burner shown in the accompanying drawing comprises a casing 2 having a r0 tatable cup 3 therein to which liquid fuel is fed through the pipe 4:. Arranged below the cup and secured thereto or to the drive shaft 5 is a blower 6 which furnishes the necessary air for combustion. The drive shaft is rotated by a direct current motor 7 having a commutator 8 which is engaged by brushes 12-43 in the circuit of the battery 14.

The commutator which is of the usual insulated commutator bar construction is provlded with a plurality of insulating sections 15, preferably spaced apart regularly circumferentially and arranged atone longitudinal end of the commutator. These sections are of less length than the commutator so that they do not extend to that portion of the commutator which is engaged by the brushes 12-43. The sections 15 may be of any desired width, but I prefer to make them equal in width to two or more commutator se ents.

ngaging the surface of the commutator at the zone occupied by the spaced sections 15 is a brush 16 of less width than the section, so that as the commutator rotates contact between the brush 16 and the commutator segments is made and broken. Connect ed to the brush 16 is a circuit 17, arranged in parallel with the motor circuit, so that current in the circuit 17 is interrupted as the commutator revolves. The brush 16 is set opposite one of the poles of the motor so that the maximum electromotive force will exist 7 in the circuit 17.

Arranged in the circuit 17 is the primary 18 of a transformer, the secondary 19 of which is in the ignition circuit 21 which contains the electrode 22. The ignition circuit is completed through the cup 3 and the casing 2 to earth and the high potential ignition sparks bridge the gap between the electrode and he cup and ignite the fuel mixture.

I claim:

1. The combination with a direct current motor provided with a commutator having regularly spaced conducting segments separated by strips of insulation, of power circuit brushes engagingsaid commutator, a plurality of spaced insulating sections of greater width than the insulating strips arranged on said commutator, a brush engaging the commutator and adapted to wipe said insulating section, a circuit connected to said brush and an ignition circuit inductively connected to said brush circuit.

2. The combination with a direct current motor provided with a. commutator having regularly spaced insulated conducting segments, of power circuit brushes engaging said commutator, a circuit in shunt on the power circuit and having a brushcngaging said commutator, means for opening and closing said shunt circuit, a transformer having its primary in said shunt circuit and an ignition circuit containing the secondary of said transformer. p

3. The combination with a direct current motor, of a commutator for said motor having commutating and interrupting zones, power supply brushes engaging the commutating zone, a brush engaging the interrupting zone, a circuit connected to said latter on the commutator brush and shunting said power circuit, a transformer having its primary in said shunt circuit and an ignition circuit containing the transformer secondary.

4. A commutator comprising a plurality of circumferentially disposed regularly spaced parallel insulated commutator bars,

several of the bars being cut away at one end and insulating section's disposed in the depressions formed by cutting away the bars.

5. A commutator comprising a. plurality of circumferentially disposed regularly spaced parallel insulated commutator bars, the successive bars being of different lengths whereby spaces between the successive bars are formed at one end of the commutator and insulating sections disposed in the spaces and having their surfaces flush with the commutator.

6. A commutator comprising a plurality of circumferentially disposed regularly spaced parallel insulated commutator bars and circumferentially spaced insulating sections in said commutator flush with the surface thereof.

In testimony whereof, I have hereunto set my hand at Peoria, Illinois, this 17th day of July, 1918.

JOHN A. DOBLE. 

